Method and apparatus for picture transmission by wire or radio



Jan. 6, 1931. E. F. w. ALExANDERsoN ETAL 1,787,851

METHD Aub APPARATUS Fon PICTURE 'r-RA-Nsnrssrou BY wim 0R RADIo Filed oct. 2o, 1:5123

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Jam.l 6, 1931. E. F. w. ALx-:xANnr-:RSON ETAL 1,737,851

"METHOD AND APPARATUS FOR PICTURE TRANSMISSION `BY WIRE ORRDI Filed Oct'. 20, 1925, SfSheets-Sheet 3 'uam man1 cAsmeT sHuTTER 46 LEM) SCREW THREAD WHE ATSTONE TRANSMITTER INVENTOR E.F.W.ALEXANDERSON 'wagt n. H. RANGER n @Xa/WL ATTORNEY vPatented "Janiv 6, 1931 UNITED STATES PATENT-orner.

i ERNST F, W. ALEXANDERSON, OF SCHENECTADY, AND RICHARD HOWIJAND RANG-ER,

OF BROOKLYN, NEW YORK, ASSIGNORS TO RADIO CORPORATION OF AMERICA, A COR- roRA'rIoN or DJsLAwABE METHOD AND APPARATUS FOB. PICTURE TRANSMISSION BY=WIR OR 'RADIO Application led October 20, 1923. Serial No. 669,688.

Thisv inventionrelates to a new process and an arrangement for utilizing existing wire or Wireless telegraph or telephone clrcuits andl apparatus for the `transmission of pictures and the like. We are aware that many attempts' havebeen made in thepast to provide a practical and reliable system for the transmission of pictures, more especially by wire. Thesesystems generally are based on the transmission and simultaneous reception of electrical impulses of varying intensity corresponding to the light intensity of a suilicient number of Vunits of the picture so that each unit 'can be represented by a single intensity value of the electric current. The direct -v result of simultaneousI operationis a need for extremely accurate synchronization, such as has not been practically or economically possible in a commerclal telephone or telegraph system. 4

The present invention contemplates a method and system in which synchronization in its ordinary sense is unnecessary, and in Which' coordination is accomplished without actual synchronization. 4

The present invention also contemplates a system in'which the usual form 'of telegraph transmitting and `receiving circuits, both Wire and Wireless, are utilized without change, and moreover, a system in' which a mechanical transmitter, adapted to be controlled bya perforated record tape, is utilized providing for transmission of pictures at a; high rate of speed. I

In accordance with the broad aspect of our invention the necessity for simultaneous'synn chronous operation is avoided bytranslating the succession of light intensities into a record. The record may be made either at the transmitter or the receiver or at both. The current of a telephonie transmitter' system will be modulated or the current of a telegraphic system interrupted in accordance with the succession of light intensities.` This 'modulated lor interrupted current may then be put directly on the wire or on the air,

' received, V recorded and reproduced or it may be re.'v orded, transmitted, received 'and reproduced or recorded, transmitted, received, re-

corded'and reproduced. Usually the modulated or interrupted current will correspond to a certain succession of 'light intensities or a line of the picture and the record in coordination with the reproducing apparatus 'will determine the starting point of each new line or succession of impressions.

The invention may be applied to transmission of pictures with waves or currents of varying intensity similar toV telephonie cu-rrents and to interrupted or telegraphic Waves or currents. For convenience a particular embodiment will be described in connection with transmission by telegraphic-impulses as certain features of the invention are particularly ap licable thereto.

In accord'snce with our invention as illustratedin the particular embodiment to be described, the light intensity of areas of the picture are translated into impulses having durations corresponding to the light intensity. Preferably, all of the impulses are of the same'. intensity. These impulses are alsol At *the rein the method may be and vpreferably is in.

the vform of ordinary types of automaticrecorders andperforators used in telegraphy.

This is preferably accomplished by providing means whereby the picture to be transmitted may beconvertedinto a record tape adapted to control a mechanical transmitter to send impulses of varying duration depending upon the intensity of light in a small section of area of the picture. A receiver is provided adapted to convert received impulses into a perforated record tape in all respects similar to thatV produced at vthe transmitting end which was utilized to control the transmitterand by providing suitable reproducing "ly'f #Referring to Fig.

45 drum, we provide provide a system of thefclassdescribedequally adaptable to wire or radio telegraphy and i without disturbing in any way the usual apparatus found in such systems.

It isA a'further object of o ur'invention to' provide a systemv which shall be relatively simple in operation and comparatively economical to install.

It is a further object of our-'invention' to provide a system of the class described .utilizf ing an automatic mec-hanical transmitter and "mechanical receiver, whereby pictures may be transmitted and received at a relatively high rate of` speed and without the services of a skilled operator. l

'20 It is a further -object of our invention-to provide va system of the class described in which transmission Iand reproduction ot the picture may take place independentlyat anyT convenient time. Y 1 Stillother objects of our invention will be ap arentfrdm the specification.

ur invention is illustrated, panying drawing in which,

Figflshows diagrammatically f they elen' the accomments comprising the. transmitting system,

Fig. 2 shows diagrammatically the elements comprisingthe receiving system,

Fig. 3 shows in transmittercircuits and apparatus, and

Fig. 4 shows in detail a portion oftherecordercircuits and apparatus.

1, there is4 provided va rotatable transparent cylindrical drum 1, upon which the picture to be transmitted is V adaptd"to"be,mounted. Withi'nsaid drmn is provided a suitable sourcejof light 3 which may' conveniently be an 'ordinary electric light bulb centrally disposed therein.- Arranged4 at a convenient v.distance from said what may be termed a perforator controller? 5 which'comprises for example a light sensitive-cell and circuits conf. trolled thereby. Alens 4 is interposedbetween the drum 1 vand the perforator controller 5o 5 ina manner toconcentrateV the light upon the sensitive cell. Suitable'mea'ns for rotating the drum 1 at a proper speed is provided, such for instance as motor' 2. Also, provision is made for causing longitudinal movements either of the drum 1 or of the perforator con- -troller 5 and lens 4 -in such aman'ner that.

as the drum is rotated, Alight fromvall parts of the picture to be transmitted is progressively thrown upon the lightsensitive'cell.

om the shaft of the drum meshes with a `worm 2 on the shaft of themotor and with a gear.

4. having a screw and I af general way operation of a system embodying the invendetail aportion of theA for utilizing the variation the cell. Thev arrangement herein shown has -a terminal of said cell connected to suit able described, o0 For producing rotation of ther-cylinder andv the relative longitudinal movement a gear 3 Y threaded shaft 5 for mov- .consisting of 'o5 mg the lens and perforator controller longi provided forate a tape in a manner vto be descri ed. The perforatedtape lis utilizedv to control a into the'tran'smitter, this is not necessary and if'desired'fa large number of pictures may be converted into records and the records stored away until it is vdesired'to transmit the pictures'. While nol transmitter circuits have been shown in this figure, it will be obvious that the transmitter 7 may control any suitable circuit, for instance a wire telegraph line in the usual way, or a wireless telegraph system, as will be readily understood by those skilled in the art.

Referring to Fig. 2, which shows diagrammatically the elements comprising the re# ceiving system, 8 is a receiver, either wire or wireless, adapted to control some suitable apparatus for making a perforated tape record of the impulses received, such for instance asa Creed re erforator 9 well known in the art. The pergdrated-record tape is fed toreproducer 10 which reconstructs the picturefrom-therecord tape in a manner to be described hereafter.

the general construction and tion, the arrangement and operation will -now bedescribed in greater detail.

lens 4 on photo-electric cell 11. This invention is not limited to the use of a light cell and any suitable arrangement adapted to give a measure of the intensity of lightl may be substituted therefor.

- Various arrangements may also be utilized of resistance of battery 13 which 'for the pirticular arrangement used may have an M. F. of about Having indicated in tudinally. Suitable electrical connections are between the perforator controllerI 5 and a suitable perforator 6 adapted to eri so i 400 volts. The positive terminal of battery 13 is connected to resistance 12 of avery high value, for instance`20 megohms. The other end of resistance 12` is connected to the other terminal of photo cell 11. For operating 'the systemin the manner to be hereinafter the change in the voltage. drop across the high resist-ance 12 is utilized. This is most conveniently accomplished through the aid ofanA amplifying system such asa three electrode thermlonic valve ampliier ing tubes connected in any well. known manone .or more standard amplifyner. For simplicity a single tube is shown although this 1s purely diagrammatic as suficient amplification will be used to enable operation-of the relays hereinafter referred to.

The grid of this tube is connected to the negative terminal of resistance 12 and the plate is connected .thru series connected windings O, of relays 21,22, 23, 24 and 25 to a suitable source for maintaining them positive, in this case shown as the +110 terminal of a three wire' 110 volt supply line, the neutral terminal 0 of which is connected to the lilame-nt of the tube 16.

One terminal of potentiometer'14 is connected to said neutral, the other terminal being connected through resistance 15 to the adapted to be traversed by a conducting arm' rotated by motor 2. The rotating arm is connected to the' 110 side of the threewire supply line. One segment of said commutator is connected through punching coil 20 of the perforator to the neutral. yThe armatures of relays 21, 22, 23, 24 and 25 are connected also to said neutral and the armature of relay 21 closes a circuit through perforating'coil 31 to the -110 side of the three wire supply line. In the same way armature of relay 22 closes the circuit through perforating coil 32 and armatures of relays 23, 24, 25 close the circuit through perforat-v ing coils 33, 34 and 35. v

vEach of these relays 21, 22, 23, 24 and 25 comprises two windings, an actuating winding designated as A which is arranged to attract its armature against'the fixed contact and close the circuit through the perforator coil and an opposing winding 0 arranged to hold the said armature away from its contact leaving the perforator coil circuit open. Each of the actuating windings A of relays 21, 22, 23, 24 and 25 1s connected on the one hand to the neutral of the supply source and` on the other hand to the adjusting arm of potentiometers 26, 27, 28, 29, 30 and connected inparallel between the positive and neutral terminals of the three w1re supply, the purpose of which will be explained later.

Any suitable device ma be used'herein t'or the purpose of perforatlngtape 36. Sat-v isfactory results have been obtained bythe use of the Kleinschmidt perforator, wellknown to those skilled in the art. It may be stated that the perforating coils 31, 32, 33,

34 .and 35 do'not, by their energization in the lusual arrangements actually vperforate the tape, but they control the setting of the punches corresponding thereto for operation and the' paper is perforated by the action of rpunching coil 2O..-

As shown in the drawing all of the perforator coil circuits are open when there is no illumination on the picture and none of the punches are set for operation. The same would ,of course be the situation when the light is thrown on a dark spot. When a light spot or hich light is projected on the lens all the relnays are closed and the punches are set for operation. However, it 'is/ not material whether the arrangement is co-ordinated to operate the punches for dark spots or high lights ,as reversals may be readily accomplished by reversals at any point in the transmitting or'receiving apparatus. As

the -perforator is a well-known type it will be unnecessary to illustrate anything but its essentials.

' Referring now to the operation of the apably at one corner of the picture to be transmitted. A suitable gear ratio is employed between motor 2, drum 1 and commutator 19 so that one energization of the punching coil takes place` for 1/32 of an inch of rotation-of the drum. If closer detail is desired the distance maybe made less. The light from the picture falls upon 'photo cell 11 and the current therefrom is varied in a ywellknown manner; that is to say, when no light falls upon the cell the resistance has a predetermined value.V The greater the amountA of light falling upon the cell, the lower this value becomes and the greater the current iiowing through the cell and also through resistance 12. Inasmuch as the value of resistance 12 is Ahigh the drop in potential between the terminals of this resistance will liuctuate with the current and therefore in accordance with the` intensity of light in the picture to be transmitted. It will now be seen that the grid of tube 16 will receive a negative charge which will be greater in cell 11 `is large. That is, the lighter the picture in a particular section, the. greater" the negative charge lof the grid of tube 16 and the' less the plate current.- Potentiometer' 14 is adjusted in a manner so that this negative charge gives a suitable ei'ect in cutting down the plate current to satisfactorily operate the relays 21, 22, 23, 24 and 25 in the manner hereinafter described'.

trolling'relays 21, 22, 23, 24, and 25 and f spots on the picture.

-shown relay 21 is adjusted to openawith tentiometer 14 are adjusted so that the perforator coils 31, 32, 33, 34, 35 are closed when the-plate current is a minimum due to projection of a high light value, that is, theactuating coils are stronger in their attrac- Ktion. under this condition. The strength of smaller current in opposing coil O than any of the other relays; `relay 22 upon a predeterminedvincrease in plate current and relays 23, 24 and 25 successively thereafter, if the dark spot increases the plate current suiciently. Briefly, the light value determines the number of perforations which are made decreased to suchv on the taper In the arrangement connected as shown, the plate current varies inversely with the light values. The hi hest light values of the picture give-a re atively strong negative bias on the grid of amplifier 16 through the action of resistance 12 whereby t-he plate current flowing through the o posing windings of relays 21 to 25 will' e a value that all of said relays will be closed by the superior -attractlon of the actuatin coils A and coils 31 to 35 will be energize The perforator is soV arranged that by this energization all of the the energization of t 35 punches will be pre ared for operation on e punching coil 2O by subsequent closure of punching coil circuit through commutator '19. It is apparent there ore that a high light in the picture causes perforationof the tape .by all of the punches as shown. The circuit arrangements described are one means for determining light values and translating them into a form which may be transmitted and vreceived as impulses of varying len h. Although the arrangement shown for t is purpose is a desirable one other arrangements may be used some of v which will be the subject matter of separate applications. The present application willcontaingeneral claims to. the novel sub]ect matter common to the various arrangements." f

Immediately upon the operation of the l punching coils and-the punching of the tape i the same is stepped forward to a new position.

l may be stated at` this-time thatthe perrations lB B made inthe lower row andsities of different 'unit areas. :When put through the.v transmitter theperforation B comes into action priorto perforation B', due to the fact that the fingers cooperating therewith act alternately.

vstartsthe impulse. The impulse then continues until another perforation is reached i i *the picture or cut from the tape.

The perforations Bf fof thetapecause a' circuitto be closed which shown the lnext succeeding perforation E in the top row following B marks the termination of the said impulse and it will be seen that for a high light in a picture which causes the operation ofperforating coils 31 to 35 inclusive, the impulse whose beginning is initiated byfperforation B will be almost immediately terminated by the first perforation E. Although the succeeding perforations are made by the coils 32, 33, 34 and 35 theyhave no effect when the'apparatus is operated in the particular manner described as no impulses are again transmitted until the next perforation B is reached when the tape is fed into the transmitter. For a Value of light not quite so intense as that which causes the operation of all said relays, the re- "When -a closure of the punching coil circuit occurs, the tapewill be punched in a corresponding manner. In this case, however, an impulse of threey times the length of the preceding`one will be indicated by the tape inasinuch'as perforation E will not be made and perforation F will be the first perforation following the perforation B which marks the beginning of an impulse. When the tape is passed through the transmitter, the impulse sent will be three timesas for a high light. In like maner, as the lights of the picture are less intense and the plate current through the tubes increases relays 23,24 and 25 will remain of the picture and the impulses corresponding thereto will be ,indicated by the-space. intervening between initial impulse B and the terminating perforations G, H and I.

lIt will beseen therefore that each group of perforations represents a succeeding differential section ofarea of the picture to be transmitted andwith the record tape so -prepared may@ in a manner so length or time duration will be transmitted be used to control ya transmitter 'in acordance with the intensity of light in the lparticular differential section of area. To economize in transmitting time, parts 4of the picture ,which are non-essential or contain no distinctive outlines maybe either cut out of For instance, in'transmitting a pictureA of the head and shoulders of a man from a picture three inches .square it may be 4convenient to eliminate the two upper corners about 1% wide by 11/2" lon as -these contain no details of interest'. If t 's is to be donethetransmitting relays 22,

long as that sentv open for the shadows lll) that an impulse of varying recorder 9 may conveniently be a'Creed re perforator. The operation of receiver 8 and recorder 9 is well understood and it is notbelieved necessary to 'describe i-t in detail ex- 1 cept so far as necessary to understand the method of reproduction of the picture. `It

willbe seen that the operation of the elements thus far described produces a record tape at the transmitting end having indications thereon ofthe 'duration of impulses corresponding to the light intensity of a particular sect-ion ofarea of the picture to be transmitted and an identical record tape at the receiving end. This latter record tape may then be utilized in any suitable reproducer to reconstruct the picture.,

A suitable reproducer adapted to-utilize thetape recordmade at the receiving` end is shownin Fig. 4 wherein we have indicated diagrammatically a Wheatstone standard automatic transmitter unit. As the operation of this transmitter unit is well under- .stoodby those skilled in the art it Will mit "be yparticularly described except as it co-acts with the reproducer. Transmitter T is driven through a suitable motor, not shown 'and is adaptedV to cause vprogressive movement of the tape37 through its housing. The transmitter is adapted to open and close a circuit including magnet 4 6 and battery 47 for intervals in accordance with the perforations of the tape. Magnet 46 controls any suitable recording means herein shown by way of example as a light recorder. Tape 37 is also geared through the middle or guide perforations with drum'43 and driven through the driving motor of the Kleinschmidt perforator which is adapted to have secured thereon a suitable sheet of light sensitive filmv upon which the picture is to be recorded.

The light recorder may consist for example,

of a light proof cabinet L14/for drum 43 having a slot 45 the edges of which'serve as guides for a housing 38 movable longitudinally on the guides. `The' housing contains .a light. 39, and a lens 40, for projecting light through the slot into the casing containing the photographic Hlm onwhich the picture is tobe recorded. The magnet 46 controls the opening and closin of a shutter 41 interposed-between lthe lig t and lens and thus.L controls the exposure ofthe film. The mag` l net willfhearranged'so that when the tape is perforated in such a manner as to correspond to a high light (short impulses and long spaces) of the picture, shutter 41 will be closed momentarily and then vpractically instantly opened so that the proportionate time of light exposure of the iilm is long. For a less intense high light the shutter wi l remain closed fora longer period causing less exposure and in a similar manner the length of theexposure ofthe film will decrease in accordance. with the length of time the shutter is maintained closed wherebyv dots will beproduced Whose intensity corresponds to the length-of the impulse transmitted. It maybe stated that .any suitable means is utilized to cause travel of the shutter with respect to the exposed portion of the drum 43 such, for instance, as rotational movement of drum 43 and translational movement of thread driven through shaft .which drives the drum and the perforated record.

Itwill be evident that the speed of drum 43 is entirely independent of that of the drum 3-of the transmitter because reproduction may be independent of reception and recording. The only condition which must be fullilled isthata definite number of operations "of a punching coil in a reproducer must take place foreach complete rotation of the drum 3 and drum 43 must be chosen of such size or its speed so governed that the same number of perforation groups or impulses correspond to a complete revolution thereof. That is, the receiving end should provide for the same number of impulses per row as are transmittedv by the transmitter per row. This, however, is taken care of in the design of the apparatus by providing the proper gear ratio between the elements causing relative movement between the shutter and drum 43 and those causing movement of tape 37.

While We have shown and described a photographic recorder for reproducing a` picture it is evident that our mvention is not limited thereto but that any other suitable recorder such as a chemical recorder may be used adapted to produce on the surface of drum 43 an impression the size or intensity of which is proportional to the length of the transmitted impulse. 1'

the light 39 and lens 40 by means of a screw i By means of the arrangement described it will be noted that we utilize a process for transmitting pictures and the like which 1s Vessentially simple and reliable and which is free from .the defects inherent incertain methods. It is also to be `noted that we have avoided the necessity for simultaneous syn- 4 chronous operation of the transmitting and receiving drums. Both the transmitter and the reproducer may be run independently at aspeed as fast as their construction will permit. It is also evident that the' reproducing of the picture may vbe stopped at any time therefrom, translating the current representing unit areas into a record in which each. g unit area 1s represented on .the record by an area, and a complimentary interva without" interfering with the operation of the transmitter `in order to make any adjustments which may be desired or to utilize the circuit for more ur ent business.

` Having describe our invention what we claim is 1. A method of transmitting a Vpicture i which consists in illuminating .the picture,l

conveying light from unit areas in succession to alight sensitive cell, converting the light intensity of successive areas into currents of x different intensities, and` producin a record therefrom in which each of the unit areas is represented by a section therein of the same indication having a duration proportional to its light intensity, transmitting electrical impulses of correspondin length, receiving the electrical impulses an indicating themon a l surface in positions correspondin to the location of the unit areas correspon ing thereto. v l' 3'. A method of transmitting pictures which consists in illuminating the picture,con veying light from unit areas thereof in succession to a photo-electric cell, converting l variations in light'intensity from successive areas into variations in current intensity therefrom,l translating the current representing unit areas into a record in which each unit area isv represented on the record by an indication having akduration proportional to its light intensity, transmitting electrical impulses of correspondin length, receiving the electrical impulses an indicating them on, a surface in positions corresponding to the location of theuiiit areas corresponding there- -which consists 4 in illuminating the picture,

-to, with exposures having a time .duration Corresponding with the duration of the re.- ceived impulses. v

4. A method of transmitting pictures conveying light from unit areas'thereof in succession to a photo-electric cell, converting variations in light intensity from successive -areas into variations in current intensity therefrom,^t`ranslating the current representing unit areas into a record in which each of the unit areas is represented on the record by a section of the same duration, each section comprising an indication having a duration the i unit proportional to its light intensity and a vccmlimentary interval, transmitting electrical impulses of length corresponding to the indication, receiving the electrical impulses and indicating them on a surface iii positions correspondin correspon 'ng thereto.

'5. A method of transmitting pictures conveying light from unit areas thereof in succession to a photo-electric cell, converting variations in light intensity from successive areas into variations current intensity.

therefrom, translating the current representing unit areas into a record in which each of the unit areasis represented on the record b a .section of the same duration, each scc- .to the locationofthe unit area which consists in illuminating the picture,

tion comprising an indication having a duration proportional to its light intensityand a complimentary interval, transmitting electrical impulses of length corresponding. to the indication, receiving the electrical impulses and indicating them on a surface in y. positions corresponding to the location of the unit area corresponding thereto, with exposures having a time duration corresponding with the duration of the received impulses.

6. A method of transmitting pictures which consists in illuminating the picture,

conveying lightfrom unit areas thereof in succession to a photo-electric cell, converting variations in light intensity from successive areas into variations in current intensity therefrom, translating the current representing unit areas into a record in which each unit area is re resented on the record by an indication having adur'ation pro ortional to its light intensity, transmittin e ectrical impulses of corresponding lengt and of. substanti lly equal intensity, receiving the electrical impulses and indicating them on a surface in positions corresponding to the loca- -tion of the unit areas corresponding thereto.'

7. A methodl of transmittirg pictures which comprises, illuminating :t e picture, transmitting .light from unit areas lthereof in successionto a photo-electric cell, producing therefrom. a corresponding fluctuating current output andv thereby-'producin from the picture to be transmitted a' `pe'r orated record tape, each perforation 'ofsaid tape corresponding-'toa diiferentsection of.

area of said picture andthe length bf the perforation in each perforation unitfbeiiig de pendent upon the intensity inthe cor-' .which comprises illuminating the picture, transmitting-light from unit areas thereof in succession to a photo-electricl cell, producing therefrom a corresponding fluctuatingv curpicture to be transmit perforated recv ord tape comprising a p ty -,of perforarent output and .thereby roducing from' the tensity of light in thedifferential section of said picture corresponding thereto.

9. The method of transmitting pictures which comprises illuminating the picture, conveying illumination lfrom unit areas thereof to a photo-electric cell, producing therefrom a series of impulses corresponding to differences in illumination of the successive areas, transmitting a series of impulses corresponding to differential sections of area of the picture to be transmitted, controlling .the duration of each'of said impulses according to the intensity of light in the differential section corresponding thereto, receiving such impulses, recording thev same by perforating a record strip or tape and reproducing-the picture from said perforated strip.

10. In a transmitter for pictures and the like, the combination of means for perforating a record tape, means for` controlling a transmitter from said perforated record tape, a series of relays each responsive to different strength currents for controlling saidperforating means, and means sensitive to the iny tensity of light falling thereon for' controlling said controlling meansfor said perforating means, whereby said perforating means will perforate said tape with marks of varying duration, said marks being proportional f t'o the light intensity of the pi'ctureNbeing transmitted.

11. In 'a transmitter for pictures and the like, the combination of means for perforatmg a record tape for controlling a transmitter, means comprising a plurality of relays for controlling said perforating means, and means sensitive to the intensity of light falling thereon for controlling said controlling means, whereby said controlling means is adapted to actuate said relays to perforate said tape in varying time durations which are directly proportional to the light intensity of the picture being transmitted.

12. In a transmitter` for pictures andthe like,`the combination of means for perforat-e ing a record tape adapted to Icontrol a trans,- m1tter, means for controlling said perforatingmeans comprising a plurality of relays, eac having an actuating winding and an opposing winding, and means sensitive to the intensity of light falling thereon for control- @ling said controlling means.

' 13. In a transmitter for pictures or the like, the -combination of means for perforating a record tapeiadapted to control a transmitter, means for controlling said perforating means comprising a plurality of relays, each com-v prising an actuating winding and an opposing winding and said relays being so constructed and arranged as to 4be successively operated in accordance with predetermined increases in the current owing therein, and means sensitive to the intensityof light fall- 'mg thereon for controlling said controlling means.V

14. In a transmitter for pictures or the like, the combination of means for perforating a record tape adapted to control a transmitter, said perforating means comprising means for making a perforation to indicate the beginning of an impulse and a plurality of means for making a perforation indicating the end of an impulse whereby the length of` impulses may be controlled, means for controlling said perforating means, comprising al plurality ofvrelays and means sensitive to the intensity of light falling thereon for controllin said controlling means;

15. n a transmitter for ,pictures and the like, the combination of means for perforating a record tape adapted to operate a transmitter said means beino constructed and arranged to strike a perforation marking the -beglnning of an impulse and having a plurality of punches adapted tol strike perforations at varyingl distance therefrom to 1nd1- cate the termination'of an impulse, a plurality of means for controlling said plurality of( punches `-comprising a plurality. of relays, said relays being adapted to be operated successively in accordance with current therethrough and means sensitive to the intens1ty of light falling thereon for controlling said controlling means.

16. In a transmtter for pictures and the like, the 'combination of means for perforat ing al" record tape adapted to control a. trans- .mitter, said perforating means comprising a punch adapted to make a perforation marking the beginning of an impulse and a'plurality of punches, each adapted to make a perforation at a different distance from said initial perforation marking the terminationof an impulse, a coil for controlling each of said punches, a relay for controlling each of said coils, said relays'being constructed and arranged to operate successively upon predel termined increases of current and means sensitive to the intensity of light falling thereon for controlling said controlling means.

17. In a transmtter'for` pictures and the like, the combinatiomof means for perforating a record tape adapted to control a transm1tter,'said means comprisinga punch adapted to make a perforation marking the begin- 11ov p ning of an impulse, a plurality of punches, 1

- each adapted to make a perforation marking an im ulse of different length, a plurality of coils or preparing said last named punches, a plurality of relays for. selectively energlzing said coils in accordance with'the value of current flowing through said relays, means sensitive to the intensity. of .light falling Vas thereon for controlling said controlling means and means comprlsing an interrupter for causing the periodic operation. of said perforating means. i;

18. In a telegraph transmitter forp1ctures or the like the combination of meansfor perforating' a record ta e adapted to control a. transmltter, means or controlling said Pe forating meansv comprising a plurality o relays, each comprising an actuating winding and an opposmg w1nding, and means -to vary the amount of opposing torque developed and means sensitive to the intensity of light falling thereon for controlling means. v In testimony whereof.

ERNST F. W. ALEXANDERSON. RICHARD HOWLAND RANGER.

menen controlling said 

